Hitherto, a tape library apparatus has been used as a memory device or a storage device in a computer system. The tape library apparatus usually has a combination of a plurality of tape drives and shelves (cells) in which magnetic tapes are accommodated. A tape drive is referred to as a tape drive hereinafter. The tape library apparatus is used for the purposes of data backup, improved continuity of business activities, interlocking between different types of server apparatuses and so on. The tape drive may write data to the magnetic tape and/or reads data from the magnetic tape which are mounted in the tape drives from the cells.
The tape library apparatus has a plurality of tape drives and data may be written and read to and from the corresponding tape drives independently. For example, designated data or data group is backed up to a predetermined magnetic tape or a magnetic tape group including a plurality of magnetic tapes in backup process.
The backup processing according to a conventional technology provides a magnetic tape to write and read for each designated data. Data are stored on magnetic tapes independently. Thus, the tape library apparatus is required to have the equal number of tape drives to the number of magnetic tapes.
Conventional technologies are described in, for example, Japanese Laid-open Patent Publication No. 2006-294240 and Japanese Laid-open Patent Publication No. 2000-339820.